We are examining one and two dimensional polyacrylamide gels of membrane preparations from male and mutant male strains of Escherichia coli K12 in order to identify F tra operon products and intermediates in F-pilin biosynthesis. We are examining the chemical differences between F-pilin and an F-pilin precursor protein we have identified. We are examining the regulation of F tra gene expression, the turnover of tra gene proteins we can identify and the factors affecting the expression of these proteins.